REPTILES. 
51 
ming : they always hum as they are descending. Is not their 
hum ventriloquous, like that of the turkey ? Some suspect it is 
made by their wings.* 
This morning I saw the golden-crowned wren, whose crown 
gutters like burnished gold. It often hangs like a titmouse, with 
its back downwards. 
Yours, &c. &c. 
LETrERXVII. To T. PENNANT, Esq. 
DEAR SIR, Selhorne, June IS, 1768. 
On Wednesday last arrived your agreeable letter of June the 
10th. It gives me great satisfaction to find that you pursue these 
studies stiU with such vigour, and are in such forwardness with 
regard to reptiles and fishes. 
The reptiles, few as they are, I am not acquainted with so well 
as I could wish, with regard to their natural history. There is a 
degree of dubiousness and obscurity attending the propagation 
of this class of animals, something analagous to that of the cryp- 
togamia in the sexual system of plants ; and the case is the same 
with regard to some of the fishes ; as the eel, &c.t 
The method in which toads procreate and bring forth seems to 
be very much in the dark. Some authors say that they are 
viviparous : and yet Ray classes them among his oviparous 
animals ; and is silent with regard to 
the manner of their bringing forth. Per- 
haps they may be eco) fxev ljotokoi, 
l^w de ^looroKoi, as is known to be the 
case with the viper.;!: 
The copulation of frogs (or at least 
the appearance of it ; for Swammer- 
tive proportions. The females and young- of the two European redstarts are extremely alike, bu 
of these one is excessively rare in this country, and was unknown to the author. The black red- 
start can only just be considered a British bird. — E». 
* There is every reason to think this is the true cause. — Ed. 
t It was reserved for Mr. Yarrell to demonstrate the mode of propagation of the eels {anguilla)i 
and to show, in the most satisfactory manner, that they deposit their spawn like other fishes . 
For a most interesting and minute detail of his investigations on the subject, see a memoir, by 
that gentleman, in the form of a letter, published in the second series of Mr. Jesse's Glean- 
ings in Natural History," where this very long disputed question is at length completely set at 
rest. — Ed. 
t Of our three species of ophidian reptiles, the common, or ringed snake {nutrxx torqnatus) 
